Our laboratory has recently discovered a novel endo-glycosidase (Endo-ABase) in the culture fluid of Clostridium perfringens. The long-term goal of this research proposal is to isolate and characterize EndoABase, a medically useful glycosidase that may be capable of converting type A and type B red blood cells into blood type insensitive cells for transfusion. To achieve this goal, Endo-ABase must be produced in large enough quantity to destroy the blood group A and B activity of red blood cells before transfusion. Four specific aims have been proposed for this project. (1) Endo-ABase will be purified from the culture supenatant of Clostridium perfringens by a series of gel filtration, ion-exchange, and affinity chromatographies. (2) The properties of Endo-ABase will be characterized--stability, optimal pH. substrate specificity. etc. (3) Peptides generated from Endo-ABase will be sequenced, the gene of interest will be cloned, and the recombinant enzyme will be expressed on a large scale in E. coli or other suitable expression system. Finally, the recombinant enzyme will be used to treat type A and type B erythrocytes.